Influence of Coating Granulation Process on Iron Ore Sinter Quality and Productivity

For better blast furnace performance, there has always been a need for better quality raw materials like sinter, lump ore, and pellets. Among these raw materials the usage of sinter in blast furnace is at higher side compared to other iron bearing materials. As the quality of sinter product improves, its usage in blast furnaces also increases. Iron ore fines are the main source for sinter making. To improve the sinter properties it is necessary to provide good quality of iron ore fines. Due to depletion of high grade iron ore resources, goethite and limonitic ore content in iron ore fines is expected to increase gradually. Usually limonitic and goethite ore are associated with higher alumina and LOI. The conventional sintering process is one of the well established processes for high quality hematite ore. It does not fully respond to the low grade iron ore associated with goethite and limonite. This has led to deterioration in sinter properties and productivity. In recent years the improvement in the quasi‐particle structure with the granulation process is an effective method for improving sinter quality and productivity. To improve the sinter quality and productivity for low grade iron ore fines, different granulation processes like the conventional one, and other two advanced granulation processes like coke breeze, and flux & coke breeze coating granulation were studied in detail by conducting laboratory pot grate sintering experiments. From the test results it was found that sinter productivity, physical and metallurgical properties of the sinter improved with flux & coke breeze coating granulation process compared to conventional and coke breeze coating granulation process. Proper selection of the granulation time is very important to achieve the desired sinter properties. In the present work detailed laboratory experiments have been carried out by varying the coating time from 30s to 110s to study the influence of flux & coke breeze coating granulation time on mineralogy, productivity, physical, and metallurgical properties of sinter. With a coating granulation time of 50s, higher productivity, higher yield, and stronger sinter (higher T.I) with lower RDI and ‐5mm size sinter were achieved.     

高铝低硅块矿工艺矿物学及冶金性能研究

研究了一种产自非洲的高铝低硅块矿工艺矿物学和冶金性能,并与几种国内外典型块矿的冶金性能进行对比.结果表明:非洲块矿是一种由赤铁矿、针铁矿和三水铝石等矿物组成的高铝低硅高铁矿石,微孔发达,Al2O3含量较高.而就其含铁品位及脉石含量而言,要明显高于国内天然块矿,但低于其它进口块矿.非洲块矿具有良好的还原性(RI80!)和低温还原粉化性能(RDI+3.15 mm达86.69!)、较强的抗热爆裂性能(DI-6.3mm1!)及与其它进口块矿相近的高温软熔特性,可与国内低铝块矿、烧结矿、球团矿搭配使用来满足高炉渣型的要求,进而控制炼铁成本、扩大原料来源.     

Influence of limestone particle size on iron ore sinter properties and productivity

Iron ore fluxed sinter is the main ferrous burden of Jindal south west steel limited (JSWSL) blast furnaces. In sinter plant fluxes including limestone and dolomite are added to improve the sinter properties of iron ore and to provide an appropriate slag composition of the blast furnace. The raw material grain size affects the sinter process considerably because the sinter productivity and quality are strongly dependent on the green permeability of the bed, which is determined by the particle size distribution of the raw materials, the granulation effectiveness and by the sintering process itself. It is well‐known that in fluxed sinter, the size of limestone affects productivity and physical and metallurgical properties of the sinter. It is therefore necessary to understand the role of limestone particle size on sinter properties and productivity. In the present work laboratory sintering experiments have been carried out with different levels of limestone mean particle size (from 0.14 to 1.83mm) to understand the influence of limestone particle size on mineralogy, productivity, physical and metallurgical properties of the sinter. Sinter productivity increased with increasing limestone mean particle size due to improved sinter bed permeability. Sinter with limestone mean particle size of 1.25 to 1.52 mm yielded better sinter strength and lower RDI compared to sinter with smaller or larger limestone mean particle size. Higher sinter strength is due to better and uniform distribution of limestone particles, and better bed permeability enabled easy assimilation and effective distribution of calcium ferrite phases. The improvement in sinter RDI is due to change in mineralogy of the sinter compared to coarser and finer limestone mean particle size.     

Influence of Magnesia on Iron Ore Sinter Properties and Productivity – Use of Dolomite and Dunite

For production of fluxed sinter the use of dolomite and other MgO bearing materials has increased in the recent past. Flux materials influence the microstructure and chemical properties of the resultant sinter. Improvement in raw material quality and use of alternative raw materials play an important role for improving the sinter quality and overall economics of iron and steel making. The physical and metallurgical properties of sinter mainly depend on the mineralogy of the sinter. Dolomite is composed of calcium magnesium carbonate and dunite consists of magnesium silicate. In the present work laboratory sintering experiments have been carried out with different MgO level (1.40 to 2.60 mass%) to know the influence of MgO on the mineralogy, productivity, physical and metallurgical properties of sinter prepared by using dolomite and dunite. Microstructural examinations of the produced sinter revealed that dunite sinter is bounded with higher amounts of hematite and less calcium ferrites when compared to dolomite sinter. Hematite and calcium ferrite phases decreased whereas magnetite phase increased with increase of magnetite content in sinter using both dolomite and dunite. From the test results it was found that dunite sinter showed better metallurgical properties whereas dolomite sinter showed better physical properties.     

Relationship Between Iron Ore Granulation Mechanisms,Granule Shapes,and Sinter Bed Permeability

The shape and size of granules are the basic factors that influence the packing structure and permeability of granular materials. This paper focuses on granulation mechanisms and the shapes (sphericities) of granules produced during the granulation of different feeds of iron ore for sinter production, using X-ray microtomography. Granule structures revealed that four mechanisms governed the formation of the granules namely autolayering, coalescence, adhesion of micropellets and two-stage layering. The addition of iron ore in the form of concentrate and micropellets to the sinter mixture enhances the mean sphericity of the granules while decreasing the sinter bed voidage and permeability.     

改善鞍钢烧结矿冶金性能的试验研究

以烧结矿碱度和w(FeO)为出发点,进行了鞍钢烧结矿冶金性能优化试验研究。结果表明:烧结矿碱度增加,低温还原粉化性和还原性得到改善;但碱度过高时,对低温还原粉化和还原性的影响不明显,鞍钢烧结矿适宜碱度为2.05~2.14。w(FeO)提高,烧结矿低温还原粉化性能得到明显改善,但烧结矿还原性变差,综合考虑烧结生产和烧结矿冶金性能,烧结矿适宜w(FeO)应控制在8%左右。     

碱度对司家营铁矿粉烧结矿矿相结构的影响

 通过偏光显微镜对不同碱度司家营铁矿粉烧结矿矿相结构及冶金性能进行了系统研究。结果表明：随着碱度的提高,铁酸钙含量明显增加,磁铁矿、赤铁矿和玻璃质含量逐渐降低;矿相结构由斑状—粒状、骸晶结构过渡到交织熔蚀结构;磁铁矿由自形、半自形晶过渡到他形晶;赤铁矿由菱形定向排列过渡到他形晶;铁酸钙主要由他形晶、板柱状过渡到针状;转鼓强度有明显增加,低温还原粉化性能和还原性都得到明显的改善。     

Effect of Iron Ore Pellet Size on its Properties and Microstructure

The properties of the pellets and their microstructure mainly depend on the raw material mix proportion, raw material chemical composition and the physicochemical conditions like the temperature and oxygen partial pressure within the induration machine. The pelletising plant products are in the size range of 8 to 16 mm. With increasing pellet size, the sintering intensity, thermo‐chemical conditions and formation of different phases vary across its cross section. The time required for varies reactions within the pellet is directly proportional to the pellet size. Because of differences in pellet size, the reduction and oxidation process takes place under different conditions resulting in different phases and microstructures. In this work, detailed studies were carried out on pellets of different size (8 to 16 mm) produced from a 4.2 Mtpa pellet plant for their physical, metallurgical and microstructural properties. It was observed that the pellets in the size range of +8 to ‐12 mm showed good strength and lower RDI. It was observed that the amount of hematite, magnetite, porosity, pore density, pore size and slag phase play a significant role on pellet strength and RDI.     

MgO对烧结工艺及烧结矿冶金性能的影响

研究了MgO对烧结工艺及烧结矿冶金性能的影响.研究结果表明,在烧结过程中不加或少加MgO,可提高烧结生产效率,获得冷态强度高、软熔带温度区间窄的烧结矿,从而提高高炉软熔带的透气性、降低料柱全压差.为保证高炉渣对MgO含量的要求,以及确保烧结矿低的低温还原粉化率,提出了合理添加MgO的新工艺.     

烧结过程气流分布对烧结矿质量影响的研究

采用烧结杯实验和现场测试相结合的方法,研究了烧结过程中气流分布对烧结矿质量的影响.通过现场测试得知,双烟道两侧各风箱支管的气流分布存在波动,烧结机上表层烧结矿表观不均匀,矿相上也存在一定差异.烧结杯试验结果表明,在现场原燃料条件下,烧结工艺参数最佳控制范围是点火负压为10～11 kPa、烧结负压11 ～ 12 kPa、点火温度1 030℃左右.按上述参数调整生产工艺,可达到提高烧结矿质量的目的.     

MgO对钒钛烧结矿产质量的影响

针对攀钢烧结生产的情况,在实验室进行了MgO对钒钛烧结矿产、质量影响的试验研究.结果表明,适当增加攀钢钒钛烧结矿MgO含量,有利于提高烧结矿转鼓强度、成品率,改善其冶金性能.从目前攀钢条件看,烧结加少量(2%～3.5%)白云石或高镁石灰是行之有效的措施,烧结矿MgO＜3.7%为宜.     

超高碱度对烧结矿性能与工艺参数的影响

 进行了超高碱度烧结, 适宜工艺参数,不同SiO2含量,烧结强化措施的实验室试验研究。试验结果表明,在碱度2.0～3.2范围内,随着碱度的上升,ISO转鼓指数上升,利用系数提高,烧结速度加快,成品率下降。在碱度2.0～2.8范围内,指标几乎成直线上升,碱度2.8以后部分指标开始出现下降趋势,碱度2.8是攀钢现有烧结矿的最适宜碱度。随着碱度的提高,烧结矿中钛赤铁矿与钛磁铁矿减少,铁酸盐含量增加,钙钛矿约有增加,硅酸盐变化不大。还原性与低温还原粉化率均得到改善,软化与熔融开始温度上升,软化区间与滴落区间减薄,有利于改善高炉透气性。在超高碱度2.8条件下,应用正交试验对工艺参数寻优,并进行了强化措施试验。在目前生产条件下有必要将碱度从2.4提高至2.8,SiO2质量分数为5.0%合适,根本途径在于钒钛精矿提铁降硅降钛。     

云南某铁矿工艺矿物学研究

对云南某地铁矿进行工艺矿物学研究,通过化学分析、X衍射仪、重砂分析、显微镜下鉴定等手段,查明矿石的结构构造、矿物组成,对有用矿物磁铁矿、褐（赤）铁矿、钛铁矿的嵌布特征及赋存状态进行了研究,对该矿石的可选性及综合利用提供了依据。     

Measures of Decreasing Blast Furnace Fuel Consumption and Improving Sinter Performance in Guofeng

To further decrease the fuel consumption of blast furnace in Tangshan Guofeng Iron and Steel Co Ltd, measures of improving the quality of sinter and pellet and the performances of raw materials were put forward through phase analysis and physical and chemical performance testing. The measures of increasing the grade of sinter, decreasing the sinter reduction degradation index at low temperature, and increasing the sinter soft melt performance at elevated temperature, as well as the reasonable process parameters of sintering were described in detail.     

包钢烧结矿的化学成分及显微结构对其冶金性能的影响

通过对包钢近三年的烧结矿质量检测数据进行多元回归分析研究,找出了包钢生产条件下,烧结矿化学成分及其显微结构对烧结矿的冶金性能的影响规律。该规律可有效地用于提高烧结矿质量,并用来指导烧结生产。     

云南某铁精矿工艺矿物学研究

通过对某铁精矿的工艺矿物学研究,查明矿石矿物组成、矿物的嵌布特征及铁和磷的赋存状态.此铁精矿中,铁矿物主要为褐铁矿、赤铁矿和磁铁矿,脉石矿物以石英、白云石、白云母、高岭石为主.最后阐述了影响选矿工艺的因素及措施.     

原位观察MgO对烧结高温特性影响研究及应用

 烧结矿靠液相固结形成,烧结过程中液相的形成和流动对烧结矿质量起着重要的作用;而随着资源的劣质化,烧结矿TFe品位呈现下降趋势。与Al2O3和SiO2等相比,MgO属于在烧结中主动性配加的成分,其大小影响着烧结液相的熔点、流动性和烧结矿品位。针对京唐混合料,首次采用高温共焦显微镜原位观察了MgO质量分数对烧结液相流动性的影响。研究发现,与不含MgO的混合料相比,配加质量分数为1.7%～2.0%的MgO后,混合料的液相初始形成和大量形成温度均高出50 ℃以上;液相流动速率也显著降低;烧结基础特性测试表明,混合料中MgO质量分数从2.3%降到0.3%后,流动性指数从0.7增大到1.9。在京唐烧结的工业实践表明,烧结实现烧结矿MgO质量分数从2.0%降至1.5%后,烧结矿指标有所改善。     

烧结固体燃料粒度对烧结矿产质量试验研究影响

为探讨济钢目前烧结原料结构条件下固体燃料粒度对烧结矿产质量的影响,通过改变固体燃料粒度中〈1mm的比例进行烧结杯试验。结果表明,随着固体燃料粒度中〈1mm比例的降低,垂直烧结速度加快,烧结矿成品率、利用系数、转鼓强度、平均粒径等指标明显改善,对降低固体燃料、烧结内返粉和高炉槽下返粉将起到重要作用。生产中应稳定四辊操作,适当放宽输出粒度范围,杜绝固体燃料的过粉碎现象。     

冀东铁精粉烧结成矿过程的剖析

为了合理使用冀东铁矿资源，用直径200mm、料层高度为430mm的烧结杯进行了实验室实验。经过剖析检验烧结后的料柱，揭示了冀东矿烧结过程中矿相的变化规律及机理，确认复合铁酸钙和正硅酸钙是在相互争夺液相的过程中生成的。